It’s like they see themselves as competitors.
I've ordered books from libraries thousands of miles away. It takes a few weeks for the books to arrive, possibly because they go 4th Class mail. But they get there eventually.
In my area, about 40 regional libraries are linked and will ship most stuff to the library of your choice. They also accept returns anywhere.
It’s fabulous except for new bestsellers.
Having both a family member and a couple friends who are/have been librarians, I seriously doubt it is a competitive instinct. I'm sure there are exceptions, but most librarians are genuinely dedicated to information freedom. (They certainly aren't getting MLS degrees for the money...)
I doubt they'll ever mail it direct to your home, though.